It is the first time the industry has experienced a sequential decline since the second quarter of 2002, when mobile PC shipments decreased by 3.7%.

The industry enjoyed a 3.9% increase during the same period last year.

Overall, the first half of 2013 saw the worst sales since 2003, posting an 11.2% fall compared to the same six-month period a year ago. In comparison, mobile PC shipments surged by 41.7% in the first half of 2010.

"Representing devices such as traditional notebook PCs as well as the new thinner ultrabook laptops, the mobile PC industry on the whole is struggling to find any momentum for growth as upheavals rock the market," said Craig Stice, senior principal analyst for computer platforms at IHS.

He added: "Despite the broad appeal of media tablets, the devices won't be able to fully replace PCs, and consumers will continue to need the computational power of personal computers.

"If a new low-cost PC offering strong performance can become available on the market and meet consumer expectations, then PCs could be set for more growth - not like the glory days of the 2000s - but growth nonetheless."

A full downturn is projected for total PC shipments in 2013, which would make it the second consecutive year of decline.